Battle of Yi Ling

The Battle of Yi Ling, also known as the Battle of Xiao Ting, was a major battle of the Three Kingdoms Period, a rare encounter between the forces of Shu Han and Eastern Wu. Liu Bei, declaring Wu his sworn enemy after their betrayal of his brother Guan Yu to Cao Wei, invaded with 100,000 troops, but was dealt a crushing defeat, in a battle which was fought purely out of vengeance, not for any strategical matters. This failure to conquer Wu cost Liu Bei two of the Five Tiger Generals: Zhang Fei, who was assassinated on the march, and Huang Zhong, who had died on the battlefront. Officer casualties were heavy on both sides of the battlefield, with Wu losing Gan Ning, Ma Zhong, and several of their soldiers.

Wu-Shu Alliance
In 208 AD, northern warlord Cao Cao, who had declared himself Prime Minister of the Han Dynasty, gathered an army of 800,000 soldiers from across the Central Plains and northern China to crush the "rebellion" of Liu Bei and Sun Quan, the former of whom was fleeing from his might, the latter of whom had established himself as King of the Wu Territory in Yang Province. The Allied Forces won an unexpected naval victory at the Battle of Chi Bi which cost Cao Cao his chance at unifying southern China in one swift blow; a protracted struggle began. The Southlanders fought in alliance against Cao Cao's Forces until 209 AD, when they had evicted Cao Cao from most of his lands; Sun Quan and Liu Bei's armies began to race to take over Jing Province. Liu Bei's forces captured Changsha, Wuling, Guiyang, and Lingling, while Zhou Yu captured Nanjun, Jing Province, Jiangling, and Xiangyang. Soon, the Wu had captured the territories that Liu Bei had conquered from the Four Regional Lords in the Battle of Jing Province and the alliance was left in tatters.

The Jing Dispute
From 209 AD to 218 AD, Liu Bei and Sun Quan confirmed their domains and extended them against Cao Cao's empire in the north, with Guan Yu holding onto Liu Bei's half of Jing Province. In 215 AD, these borders were pushed westwards when Shu allowed Wu a third of Jing Province in exchange for their cooperation in an invasion of Cao Cao's lands, which resulted in the disastrous Battle of Xiaoyao Ford. Liu Bei arranged for a fresh invasion in 218 AD, promising more lands in Jing to Wu if they would invade Hefei again as they invaded Hanzhong. The plan succeeded, with Liu Bei conquering Hanzhong and Wu defeating Wei at Ruxukou. However, Guan Yu refused to budge, so Wu resolved on a surprise attack. Allied with Cao Ren, Cao Cao's cousin, the Wu launched a surprise attack on Xiangyang, which had been captured, forcing Guan Yu to lift the siege of Fan Castle to engage the Wu to the rear. It was a failure, and Guan Yu was killed by the Wu troops. Liu Bei heard of this through Zhuge Liang, and declared Wu his sworn enemies.

Preparations
Liu Bei started preparations for an invasion in 220 AD; Cao Cao was out of the problem, as he had died that year, and the Han Dynasty was overthrown. Now flying the banner of the Kingdom of Shu, Liu Bei mobilized an army of 40,000 infantry and 3,000 cavalry. Zhuge Liang, Qin Mi, and Zhao Yun advised against such an act, but when a messenger burst into Liu Bei's palace to tell him that Zhang Da and Fan Qiang killed Zhang Fei, and took his head to Wu, Liu Bei shook aside all advise. Inconsolable, Liu Bei ordered the destruction of Wu.

He marched into Jing Province, and hired King Sha Moke as a mercenary; bringing with him 57,000 Shanyue troops from his warchiefs' domains, Sha Moke added these troops to Liu Bei's army.

The Campaign
Liu Bei captured the walled cities of Zigui, Wu County, Mt. Ba, and Mt. Xing, and had to constantly shift headquarters as his forces advanced into the heartland of Wu. At Yidao in February 222 AD, Wu Ban and Chen Shi captured the city after a pitched battle, and soon, Liu Bei set himself up outside of Bai Di Castle, in a large camp that was defended by Yue Ying, Zhang Bao, and Huang Zhong; Wei Yan, Guan Xing, and Wang Pang took to the front lines. The Shu Han forces advanced along the coastline, securing the many Eastern Wu strongholds and garrisons.

The fight on the main battlefront was a different story, with Zhu Huan and Zhou Tai pushing the Shu back. Wei Yan was critically wounded in a duel with Zhou Tai, who struck him down with his saber. Zhou Tai distinguished himself by killing Sha Moke, leader of the 57,000 Shanyue mercenaries, who was trying to escape the battlefield after his defeat of Gan Ning, who was killed. The other front line unit of Huang Zhong was routed when Ma Zhong loosed an arrow into his throat, killing the 74 year-old general. The Shu Han army was also aware of Zhu Ran destroying their watchtowers, and although Zhu Ran did not achieve subtlety, he launched a devastating fire attack, riding along the mountainsides with a group of horse archers, shooting fire-tipped bows at the Shu camp. What could have been more demoralizing than a fire arrow burning down the Shu banner? Guan Suo, in charge of the camp, was able to hold the Wu out, resulting in Gan Ning's death in a failed surprise attack via the river, and Liu Bei was able to retreat to Bai Di Castle. As Lu Xun and Zhou Tai pondered how to get through the Stone Sentinels Maze, a labyrinth designed to impede the Wu in case of defeat, its mastermind Zhuge Liang, along with General Yan Yan, arrived on the battlefield, creating a waterway that connected the Wu main camp's bank to Baidi's bank. The Wu were too late to capture Liu Bei with Baidi; they found a castle with a general-less garrison; Liu Bei led his unit to attack Sun Quan's camp. In this attack, Liu Bei lost Ma Liang, who was killed while helping to escort Liu Bei to safety. Zhou Tai nearly killed Liu Bei, slashing him across the chest, and a mortally wounded Liu Bei retreated to Baidi along with Zhuge Liang. 80,000 Shu Han and Shanyue troops were killed in the battle. Wu casualties were lighter, but an exact number is unavailable.

Aftermath
Liu Bei never recovered from this defeat and died at Bai Di Castle of illness. Zhuge Liang took over Shu Han as regent to Liu Shan, the weak son of Liu Bei, and restarted the alliance with Wu, and Wu defeated a Wei invasion at Dongkou and Ruxukou soon after. The losses at Yiling cost Shu great generals, although Wu lost Gan Ning, Ma Zhong, Mi Fang, and Fu Shi Ren.